1. Field of the Invention
This invention relates to a furnace, more particularly to a heat exchange furnace that include at least one serpentine gas flow path disposed within a heat exchange space.
2. Description of the Related Art
Referring to FIG. 1, a biomass heat exchange furnace 1 disclosed in U.S. Pat. No. 4,449,510 is used to burn biomass to thereby generate high-temperature combustion gases. Ambient or fresh air is forced into the heat exchange furnace for heat exchange contact with the combustion gases. As such, the temperature of the combustion gases is reduced prior to exhaust from the heat exchange furnace. On the other hand, the ambient air is heated to form hot air that may serve as a heat source for various utilizations.
The heat exchange furnace 1 includes a heat exchange space 11 defined by a surrounding wall 12, and a plurality of conduits 13 disposed within the heat exchange space 11. A gas entrance chamber 14, an upper gas transfer chamber 15, and a gas exit chamber 16 are disposed above the heat exchange space 11. Two lower gas transfer chambers 17, 18 are disposed under the heat exchange space 11. The combustion gases flow through the conduits 13 and the chambers 14, 15, 16, 17, 18.
The aforesaid conventional heat exchange furnace 1 has the following disadvantages:                (1) The speed of air flowing through the heat exchange space 11 is rapid, thereby reducing the heat exchange efficiency of the heat exchange furnace 1.        (1) Since the upper gas transfer chamber 15 has a large volume, and since only one of the same is provided in the heat exchange furnace 1, the heat exchange efficiency of the heat exchange furnace 1 is further reduced.        